Views: 65 Author: Tuohai Pump Publish Time: 2021-04-20 Origin: www.txtuohai.com
|Compared with general horizontal pumps or vertical sewage pumps, submersible sewage pumps obviously have the following advantages:|
|1.||Compact structure and small floor space|
Since the submersible sewage pump works under the liquid, it can be directly installed in the sewage tank. There is no need to build a special pump room to install pumps and other machines, which can save a lot of land and infrastructure costs.
|2.||Convenient installation and maintenance|
Small sewage pumps can be installed freely, and large sewage pumps are generally equipped with automatic coupling devices for automatic installation, which is quite convenient for installation and maintenance.
There are no problems such as cavitation damage and irrigation and water diversion, especially the latter brings great convenience to the operator.
|5.||Low vibration and noise, low motor temperature rise, and no pollution to the environment.|
It is precise because of the above advantages that sewage pumps have received more and more attention, and the scope of use has become wider and wider.
Submersible sewage pumps have been developed from purely used to transport clean water and sewage with a small number of impurities to now can transport all kinds of domestic sewage, industrial wastewater, construction site drainage, liquid feed, etc., especially in municipal engineering, industry, hospitals, and buildings, restaurants, water conservancy construction and other industries play a very important role.
|1.||Large-caliber non-clogging submersible sewage pump|
|2.||With a knife to automatically cut the cloth strips, and the submersible sewage pump for the automatic mixing of weeds|
|3.||Self-priming sewage pump with pump body installed near the water|
|4.||Submersible sewage pump (the pump body can be submerged in the water)|
|5.||Mortar pump with good anti-corrosion and wear resistance is also a kind of sewage pump|
|This article mainly explains the advantages and disadvantages of submersible sewage pumps and how to use them.|
|1.||The submersible sewage pump adopts a unique single-piece or double-piece wheel structure, which greatly improves the dirt passing capacity, and can effectively pass fibrous materials several times the pump diameter and solid particles with a diameter of about 50% of the pump diameter.|
|2.||The mechanical seal of the submersible sewage pump adopts high hardness, corrosion-resistant, and wear-resistant titanium-tungsten material, which can make the pump safe and continuous operation for more than 8000 hours.|
|3.||The submersible sewage pump has a compact overall structure, small size, low noise, significant energy-saving effect, convenient maintenance, no need to build a pump house, and can work when submerged, which greatly reduces the project cost.|
|4.||A leak detection sensor is installed in the sealed oil chamber of the submersible sewage pump, and a temperature sensor is embedded in the stator winding to automatically protect the pump motor.|
|5.||The submersible sewage pump can be equipped with a fully automatic control cabinet according to user needs to automatically protect the pump from water leakage, leakage, overload, and over-temperature, which improves the safety and reliability of the product.|
|6.||The submersible sewage pump can be equipped with a float switch, which can automatically control the start and stop of the pump according to the required liquid level change. It does not need to be supervised by a special person, and it is extremely convenient to use.|
|7.||The WQ series submersible sewage pump can be equipped with a dual-rail automatic coupling installation system according to user needs, which brings greater convenience to installation and maintenance, and installation and maintenance personnel do not need to enter the sump.|
|8.||The submersible sewage pump can be used in the full head, and the motor will not be overloaded.|
|9.||There are two different installation methods for submersible sewage pumps, fixed automatic coupling installation system and mobile free installation system.|
|10.||The cutting-type submersible sewage pump has automatic mixing and cutting functions. It is used in the case of sewage with more impurities, such as toilet paper, stool, plastic bottles, cloth fibers, branches, etc.|
Stainless steel submersible sewage pumps and ordinary submersible sewage pumps are only different in material, which can extend the service life, but there is no difference in function.
Main Control Parameters
The main control parameters selected by the submersible sewage pump are the flow rate, head, power, efficiency, working pressure, cavitation allowance, etc. of the water pump.
Submersible sewage pump specifications and models are ZW, YW, AS, WL, QW (WQ), JYWQ, and other series.
WQ/QW type submersible sewage pumps, all operate in sewage, WQ is a non-clogging sewage pump, and QW type is an ordinary submersible pump.
The impellers of the WQ submersible sewage pump is different from the QW submersible sewage pump, and it is not easy to be blocked. They are divided into stainless steel materials and ordinary carbon steel materials.
|2.||YWQ automatic mixing sewage pump is equipped with automatic mixing of sewage and then sucking, so as to ensure that the medium density is uniform and not easy to be blocked.|
|3.||WL vertical sewage pump is the vertical installation method of the WQ submersible non-clogging sewage pump.|
|4.||YW/AS is a submersible sewage pump, which has the characteristics of a submersible pump, and is generally used in conjunction with a hose.|
|5.||The ZW self-priming sewage pump is a self-priming sewage pump, which discharges the internal air through idling until the medium fills the pump body to complete self-priming.|
Main Purpose of Submersible Sewage Pump
|The submersible sewage pump is suitable for chemical, petroleum, pharmaceutical, mining, paper industry, cement plants, steel mills, power plants, coal processing industries, and urban sewage treatment plant drainage systems, municipal engineering, construction sites, and other industries.|
|The submersible sewage pump can also be used to pump clean water and corrosive media. It can be used to pump up and discharge sewage and wastewater containing solid particles (φ20～φ80mm) and various long fiber impurities. The temperature of the sewage and wastewater being pumped up does not exceed 60℃, and the pH value is 5-9.|
Ordering Instructions for Submersible Sewage Pumps
|1.||Please provide the following parameters of submersible sewage pumps when purchasing, so that we can select the model and quote for you (the red part is required)|
|(1)||Product name and model of submersible sewage pump|
|(2)||Diameter of submersible sewage pump|
|(3)||Head of submersible sewage pump (m)|
|(4)||Submersible sewage pump flow|
|(5)||Submersible sewage pump motor power (KW)|
|(6)||Speed of submersible sewage pump (r/min)|
|(7)||Submersible sewage pump voltage (V)|
|(8)||Does the submersible sewage pump have accessories?|
|2.||If the product model of our company's submersible sewage pump has been selected, please order directly from our company's sales department or sales staff according to the submersible sewage pump model.|
|3.||When the occasion of use is very important or the environment is more complicated, please provide the design drawings and detailed parameters, and our technical experts will review and check for you.|
|4.||If there is no design drawing of the pump for the time being, you can provide us with the infrastructure drawing, and our technical department will provide you with free installation design drawings.|
|Thank you for visiting our website [www.txtuohai.com], if you have any questions, you can contact us at any time, and we will do our best to provide you with quality service.|
Current Status of Submersible Sewage Pump
|Submersible sewage pumps are widely used in municipal engineering, factories, commerce, hospitals, hotels, residential areas, etc. for sewage discharge due to their simple installation, small footprint, convenient maintenance, and no noise.|
At present, most of the sewage pumps sold on the market are vertically arranged, the pump and the motor are coaxial so that the weight of the rotating parts is in the same direction as the pressure of the impeller.
|Secondly, the submersible sewage pump is used under liquid, and the sewage medium conveyed contains impurities, sludge, and other substances.|
|Third, the submersible sewage pump is a kind of centrifugal pump. During its operation, the power always increases with the increase of the flow. When the flow exceeds the design flow and reaches a certain value, the motor will burn out due to overload.|
|In order to improve the service life of submersible sewage pumps, most submersible sewage pump manufacturers are now improving the protection system of pumps, that is, when the pump has leaks, overloads, over-temperature, and other faults, it can automatically alarm and automatically shut down for repairs.|
However, we believe that although it is necessary to set up a protection system in the sewage pump, it can effectively protect the safe operation of the electric pump, but this is not the key to the problem.
|The protection system is only a kind of after the pump fails, the remedy is a relatively passive method. The key to the problem should be to start from the root and completely solve the problems of the pump in terms of sealing and overload. This is a more proactive approach.|
For this reason, we apply the auxiliary impeller fluid dynamic sealing technology and the pump's no-overload design technology to the submersible sewage pump, which greatly improves the reliability and carrying capacity of the pump seal, and prolongs the service life of the pump.
1. Application of Auxiliary Impeller Hydrodynamic Sealing Technology
|The so-called hydrodynamic seal of the auxiliary impeller refers to the installation of an open impeller in the opposite direction and coaxially near the back of the rear cover of the pump impeller.|
When the submersible sewage pump is working, the auxiliary impeller rotates with the main shaft of the pump, and the liquid in the auxiliary impeller will also rotate together. The rotating liquid will generate an outward centrifugal force.
|This centrifugal force resists the liquid flowing to the mechanical seal on the one hand and reduces It reduces the pressure at the mechanical seal, and on the other hand, prevents the friction between the solid particles in the medium and the mechanical seal, reduces the wear of the mechanical seal abrasive block, and prolongs its service life.|
|The auxiliary impeller can not only play a role in sealing but also play a role in reducing the axial force. In the submersible sewage pump, the axial force is mainly composed of the differential pressure force of the liquid acting on the impeller and the gravity of the entire rotating part. The two forces act in the same direction, and the resultant force is formed by the addition of the two forces.|
|It can be seen that when the performance parameters are exactly the same, the axial force of the submersible sewage pump is greater than that of the general horizontal pump, and the difficulty of balancing is more difficult than that of the vertical pump. Therefore, in the submersible sewage pump, the reason for the easy damage of the bearing is also related to the large axial force.|
|If the auxiliary impeller is installed, the direction of the pressure difference forces acting on the auxiliary impeller by the liquid is opposite to the resultant force of the above two forces, so that part of the axial force can be offset and the bearing life will be prolonged.|
|However, the use of the auxiliary impeller sealing system also has a disadvantage, that is, a part of the energy is consumed on the auxiliary impeller, generally about 3%, but as long as the design is reasonable, this part of the loss can be reduced to a minimum.|
2. Application of No-Overload Design Technology of Submersible Sewage Pump
|For general centrifugal pumps, the power always increases with the increase of the flow, that is to say, the power curve is a curve that rises with the increase of the flow.|
This will bring a problem to the use of the submersible sewage pump:
|When the pump is operating at the design operating point, the power of the pump is less than the rated power of the motor, and the use of this pump is safe. But when the pump head decreases, the flow will increase (as can be seen from the pump performance curve), and the power will increase accordingly.|
|When the flow exceeds the design operating point flow and reaches a certain value, the input power of the submersible sewage pump may exceed the rated power of the motor and cause the motor to be overloaded and burned. When the motor is overloaded, either the protection system will act to stop the pump, or the protection system will fail and the motor will burn out.|
|It is often encountered in practice when the head of the submersible sewage pump is lower than the head of the design operating point.|
|One situation is that when the submersible sewage pump is selected, the head of the submersible sewage pump is too high, and the pump is used to reduce the head in actual use.|
|Another situation is that the working conditions of the submersible sewage pump are not very well determined during use, that is, the flow of the pump needs to be adjusted frequently.|
|There is also a situation where the submersible sewage pump needs to be used frequently in changing locations.|
|These three conditions may overload the submersible sewage pump and affect the reliability of the pump.|
|To be sure, for pumps without full-head characteristics (including submersible sewage pumps), their use range will be largely limited.|
|The so-called full-head characteristic (also called non-overload characteristic) means that the power curve rises very slowly with increasing flow. More ideally, when the flow rate increases to a certain value, the power will not rise, but will decrease, that is to say, the power curve of the submersible sewage pump is a curve like a hump.|
|In summary, we only need to select the power value of the motor rated power slightly exceeding the highest point, then in the entire range from 0 flow to the maximum flow, no matter which operating point the submersible sewage pump is operating at, the power of the pump will not be exceeding the motor power and overloading the pump.|
|For a submersible sewage pump with this performance, it will be very convenient and reliable whether it is selection or use. In addition, the motor power does not need to be too large, which can save considerable equipment costs.|
|The drainage pumps used in the building include submersible sewage pumps, submerged sewage pumps, vertical sewage pumps and horizontal sewage pumps. If the general site in the building is small and the displacement is not large, the submersible sewage pump and the submerged sewage pump can be preferentially used for the drainage pump. The submerged sewage pump is generally used in important places.|
|Vertical sewage pumps and horizontal sewage pumps require vibration isolation foundation, self-irrigation suction, and occupy a certain space, so they are rarely used in construction.|
Key Points for Design and Selection of Submersible Sewage Pump
|1.||The submersible sewage pump must be manufactured and produced in strict accordance with the international ISO 9906 or current relevant standards and qualified by the comprehensive performance test of the authoritative organization.|
|2.||According to the amount of sewage (waste) discharged, the water quality and the location of the sewage pool (collection well) reasonably determine the required flow and lift of the submersible sewage pump, and determine the pump specifications.|
|3.||According to the characteristics of sewage and wastewater, determine the type of pump to choose, whether to use cutting and grinding, whether to choose a vortex impeller or a runner impeller, single runner or double runner (under the same conditions, the single runner is more resistant to clogging than double runner performance is better).|
|4.||When selecting the submersible sewage pump, you should understand the average trouble-free working time of the submersible sewage pump under normal use conditions, the life of the mechanical seal, the rated life of the bearing, the design life of the motor, the insulation class of the motor, and the number of starts per hour that the motor can withstand.|
|5.||The submersible sewage pump should have leakage protection, overheating or overload protection, sealing leakage monitoring, and reliable grounding devices.|
|6.||The sewage tank outside the building can be installed with a non-closed manhole cover without a vent pipe. Indoor sewage tanks (collection wells) should be equipped with airtight manhole covers and vent pipes. The airtight manhole covers are made of cast aluminum, gray cast iron, and ductile iron.|
|7.||If the submersible sewage pump is used for corrosive wastewater, the pump body should be made of corrosion-resistant materials such as stainless steel.|
|8.||The submersible sewage pump in the basement should be equipped with dual power supplies.|
|9.||When choosing a submersible sewage pump, the material, processing accuracy, appearance of the main components of the submersible sewage pump, the necessary functions of the flow parts (a large passage, anti-winding, anti-blocking, etc.), and additional functions (long fiber cutting and tearing, automatic stir to prevent dirt from depositing and compacting, etc.), comprehensive comparison of service life, after-sales service, quotation, etc., and choose the best.|
|10.||The supporting equipment of the submersible sewage pump (control cabinet, liquid level switch, automatic coupling device, etc.) should be purchased from the supplier.|
The wearing parts need to be purchased as spare parts.
|Optional parts (pipe valves, pipe fittings, etc.) can be purchased together with the plumbing equipment of the main installation project, or the pump supplier can be asked to purchase.|
Flow Selection of Submersible Sewage Pump
|1.||The flow rate of the submersible sewage pump can be selected according to the maximum hourly flow rate of domestic drainage.|
The flow velocity of the suction pipe and outlet pipe of the drainage pump should not be less than 0.7m/s, and should not be greater than 2.0m/s.
In public buildings, a standby pump should be set up with each living drainage catchment as a unit, and it should be operated alternately at ordinary times.
If there are two or more submersible sewage pumps for the drainage of the basement, equipment room, and garage, the standby pump is not required.
|2.||When the sump can not be equipped with a drainage pipe, the pump should have an uninterrupted power supply|
|3.||When the drain and inlet pipe can be closed, the uninterrupted power supply is not required, but an alarm device should be provided.|
|4.||When pumping sewage and wastewater with large impurities, the outlet pipes of submersible sewage pumps in different collection tanks should not be discharged together.|
|5.||When pumping general wastewater, the outlet pipes of submersible sewage pumps in different collection basins can be combined and discharged according to the actual situation.|
When two or more water pumps share a water outlet pipe, a valve and a check valve should be installed on each water pump outlet pipe.
When a single water pump discharge may cause backflow, a check valve should be provided.
It is not allowed to combine the pressure drainage port with the gravity drainage pipe in the building to discharge.
|6.||When the submersible sewage pump lifts sewage containing large impurities, the submersible sewage pump should be equipped with a crushing device. When lifting sewage with more fibrous material, a large channel submersible sewage pump should be used.|
|7.||When the motor power is greater than or equal to 7.5kW or the water outlet pipe diameter is greater than or equal to DN100, the submersible sewage pump fixed auto coupling device can be used.|
When the motor power of the submersible sewage pump is less than 7.5kW or the water outlet pipe diameter is less than DN100, it can be installed with a flexible hose.
|8.||When a submersible sewage pump is used to drain the sewage collection tank, a fixed auto-coupling device of the water pump should be used to facilitate the maintenance of the water pump.|
The drainage pump should be able to start and stop automatically and manually on site.
Multiple pumps can be operated alternately in parallel or in sections.
Executive Standard of Submersible Sewage Pump
|Domestic submersible sewage pump manufacturers conduct manufacturing and product performance tests according to the following national standards or industry standards：|
|(1)||"Submersible sewage pump" CJ/T 3038-95|
|(2)||"Small submersible electric pump" JB/T 8092–96|
|(3)||"Submersible sewage pump" (recognized technical conditions) HCRJ 033–1998|
|(4)||"Centrifugal Submersible Sewage Pump" JB/T 8857–2000|
|(5)||"Sewage and sewage submersible electric pump" JB/T 5118-2001|
|(6)||"Submersible electric pump test method" GB/T 12785-2002|
|The products of foreign enterprises and foreign imported products generally follow the following standards：|
|(1)||"Machinery Standard" EN ISO 12100|
|(2)||"Electromagnetic Compatibility Standard" EN 61000-6-2, 3|
|(3)||"Test Standard" EN ISO 9906|
|"Code for Construction Quality Acceptance of Building Water Supply and Drainage and Heating Engineering" GB50242-2002|
|3.||Related standard drawings|
|01S305 "Selection and installation of small submersible sewage pump"|
AS, AV, QW (WQ), JYWQ, and other series of submersible sewage pumps are installed in two basic forms: mobile installation and fixed installation.
The installation method can be selected in accordance with the National Building Standard Design Atlas 01S305 "Selection and Installation of Small Submersible Sewage Pumps".
The mobile installation of hose connection is limited to submersible sewage pumps with motor power N≤7.5kW and discharge pipe diameter DN≤100mm.
The submersible sewage pump adopts an automatic liquid level control device for automatic control.
The type of automatic liquid level control device is in addition to the float-type liquid level switch. If the sewage contains no or only a small amount of suspended impurities, input pressure sensors and supporting secondary instruments can also be used.
The automatic liquid level control device installed in the sewage tank (collection well) should be as far away as possible from the water inlet.
If the weight of a single submersible sewage pump is greater than 80kg, the hook should be embedded on the floor or beam above the inspection hole of the indoor sewage tank (collection well) for lifting the submersible sewage pump during installation and maintenance.
In addition to the fabric-reinforced rubber hose used in the mobile installation hose connection part, the submersible sewage pump discharge pipe can be made of hard water supply plastic pipe, cast ductile iron water supply pipe, steel pipe, steel-plastic composite pipe, etc.
The pressure-bearing capacity of pipes and fittings shall not be less than 0.6MPa.
The installation method of the submersible sewage pump used in the building's fire elevator sump should be two fixed pipe connection or two fixed auto-coupling, and the effective volume of the sump should not be less than 2.0m³, and the rated flow of the submersible sewage pump should not be less than 2.0m³. Less than 36m³/h.
A control valve, a check valve, a flexible rubber pipe joint, and a pressure gauge should be installed on the discharge pipeline of the submersible sewage pump.
The control valve in the National Building Standard Design Atlas 01S305 "Selection and Installation of Small Submersible Sewage Pumps" is recommended to use gate valves or butterfly valves as needed.
Check valves are recommended to use spherical sewage check valves.
The submersible sewage pump is a vertical arrangement, and the pump is coaxial with the motor so that the weight of the rotating parts is in the same direction as the water pressure on the impeller.
Secondly, the submersible sewage pump is used under liquid, and the sewage medium conveyed contains impurities, sludge, and other substances.
Third, the submersible sewage pump is a kind of centrifugal pump. During its operation, the power always increases with the increase of the flow. When the flow exceeds the design flow and reaches a certain value, the motor will burn out due to overload.
The above problems will affect the service life of the submersible sewage pump to varying degrees.
Submersible sewage pumps are widely used in municipal engineering, factories, commerce, hospitals, hotels, residential areas, etc. for sewage discharge due to their simple installation, small footprint, convenient maintenance, and no noise.
At present, China's domestic submersible sewage pump market has a very broad prospect, and the reliability of submersible sewage pumps has been strengthened than before. However, improving the technical content of their products is still the main direction for the future development of submersible sewage pump manufacturers.
In view of the problems of submersible sewage pumps, some domestic manufacturers have focused their efforts on the development of pump protection systems, that is, when the pump runs abnormally, it will automatically alarm or cut off the power supply.
Although this method can have a certain effect, and this kind of protection is also necessary, it is not the fundamental way to solve the problem. We must also focus on improving the performance of the submersible sewage pump and take the problem from the root and solve it.
In addition, the development of products must take environmental issues into full consideration, so that the products developed are more energy-efficient and environmentally friendly.